Charging problems.. (1 Viewer)

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I changed the brushes in my 83 bj42 and it corrected the filter and brake light staying on. Until recently the filter and brake light are staying on again. Checked the the voltage acroos the board and it is reading 24.4 at idle. 24.8 at higher idle. So I opened up the alternator again to check and see if everything was in order and it was. So I am thinking voltage regulator. Is there a way to check? and if it is gone where can I get another one.. Oh ya 2 brand new batteries aswell..

Thanks
 

Ron R

Drive a Landruiser, enjoy life
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24.4 to 24.8 is low. At higher rpms you should have a value in the 28 V range (max 28.8V) So yes, your regulator could be shot.
I've never done it on this type of regulator myself but I've read somewhere people were successfull restoring the function by opening it and cleaning the contacts with polishing paper.
 
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I will take it off tonight and see what I can do about cleaning it.. hopefully that is the problem.
 
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I disconnected the regulator and put the volt meter to it to see how many volts were coming from the alternator and there was the same 24.4 so i am thinking I am back to the alternator.. what else could be wrong if the brushes are good?
 
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There's more to it.

I would suggest that you might have a failed or failing diode in the diode pack. One of the diodes could be "leaky" allowing AC to flow through.
This will present itself as a lower voltage on a multimeter because the negative swing of the AC current will "fool" the meter. If you have an oscilloscope to hand, (not many people do) you can see it.

You will have to disassemble the Alternator to get at the diode pack. Worst of all you'll need to isolate the individual diodes to measure them.
Using a multimeter on the ohms scale (or if a digital meter use the setting marked -|<|- )The diodes will have an impeadence in one direction and be open circuit the other (or will read good or open). There will be 6 large diodes which are the main rectifiers. If anyone of those diodes is faulty it will show an impeadence in both directions.
As this is one of those belts and braces jobs if one diode is faulty the others won be too far behind, replace the lot. Also check the exciter diodes too.
Alternatively you could hand the alternator to your tame auto electrician to repair but not as a box of bits because they will charge you extra for the priviledge.
 

Ron R

Drive a Landruiser, enjoy life
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I assumed you have a generator, not an alternator. IF so there won't be a diode pack in the generator. The 'rectifying' then isdone by means of the brushes.
The voltage-regulator will excite the stator to regulate the voltage (and current). If the regulator is not connected you will never reach the max values.

If you do have an alternator Tobugrynbaks instructions are good. One remark here though, if a diode is bad one could expect the batteries to go flat overnight.
 
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Diodes when faulty usually go open-circuit (i.e. nothing passes through). I have never seen a diode that conducted AC and still be operational. It's the same with transistors, they are either working or they are not.
You can check for AC by setting your multimeter on AC, this will tell you how much AC is in your system but it won't tell you the state of your diodes.

Just thought I might add that diodes can "leak", but this is a DC issue not AC.
 
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Tapage

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one question little out the main target of the thread .. if my alt it's working nice and properly charging values .. but when the engine room raise the temp ( down here the days are really hot ! ) the alt just start failing ( lowering ) in the charging duty ..

It happen in both .. my HDJ-80 and my HJ-60
 
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one question little out the main target of the thread .. if my alt it's working nice and properly charging values .. but when the engine room raise the temp ( down here the days are really hot ! ) the alt just start failing ( lowering ) in the charging duty ..

It happen in both .. my HDJ-80 and my HJ-60
It could be that you have shorted windings in your alt. A lot of the times with shorted windings (overheating causes the laquer to burn off, usually in the inner windings where it is hottest) the winding start shorting when things get warm due to thermal expansion of the copper wire. When its cool you can still have separation enough not to cause shorting.

Other things I can think of is dry solder joints, solder has melted, goes crystaline in structure, easy enough to spot.
Diodes can also be thermally effected as all semiconductors, could be your regulator too if its in the engine bay.
 
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I assumed you have a generator, not an alternator. IF so there won't be a diode pack in the generator. The 'rectifying' then isdone by means of the brushes.
?

I understand that all our cruisers have alternators with diodes inside but that some have external regulators but others (generally - later models) have the internal regulators.

Anyway - I believe that welding on your vehicle without first having disconnected your electrical system could be responsible for a lot of diode damage.

I wonder if this is the case here. :hmm:

:cheers:
 
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?

I understand that all our cruisers have alternators with diodes inside but that some have external regulators but others (generally - later models) have the internal regulators.

Anyway - I believe that welding on your vehicle without first having disconnected your electrical system could be responsible for a lot of diode damage.

I wonder if this is the case here. :hmm:

:cheers:
Well I have never welded on it but who is to say the previous owners did. Anyway I took it off today and I am taking it to the pro's for a rebuild.. What is that pump on the back of the alternator suppose to do?
 
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Well I have never welded on it but who is to say the previous owners did. Anyway I took it off today and I am taking it to the pro's for a rebuild.. What is that pump on the back of the alternator suppose to do?
It's a vacuum pump (lubricated with engine oil).

These Toyota diesels use it to provide the vacuum for the brake booster.

You'll find a "vacuum reservoir" beneath your BJ42 (under the passenger's seat) too.

FJ40 petrol engines use the vacuum created in the inlet manifold when the engine is idling or coasting (foot off the accelerator). But you'd upset the vacuum exerted on the diaphragm within our injector pumps if our diesels did that. (If manifold vacuum were used, touching the brakes would tend to increase the engine's power output - which wouldn't be safe/advisable. Not to mention the problems caused by events such as "a torn booster diaphragm"!)

:cheers:
 
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It's a vacuum pump (lubricated with engine oil).

These Toyota diesels use it to provide the vacuum for the brake booster.

You'll find a "vacuum reservoir" beneath your BJ42 (under the passenger's seat) too.

FJ40 petrol engines use the vacuum created in the inlet manifold when the engine is idling or coasting (foot off the accelerator). But you'd upset the vacuum exerted on the diaphragm within our injector pumps if our diesels did that. (If manifold vacuum were used, touching the brakes would tend to increase the engine's power output - which wouldn't be safe/advisable. Not to mention the problems caused by events such as "a torn booster diaphragm"!)

:cheers:
Off topic to the main line of this thread again... but now that I have got you here and seeing that the pump is attached to the alternator :D ..... how often does the pump need to be serviced? Mine looks like it's never been touched, so that's 30 odd years of operation.
 
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Off topic to the main line of this thread again... but now that I have got you here and seeing that the pump is attached to the alternator :D ..... how often does the pump need to be serviced? Mine looks like it's never been touched, so that's 30 odd years of operation.
Well I took mine apart after 238,857kms and 28 years service and found nothing really needed attention.

In fact, the pump was probably worse afterwards because I accidentally dropped one carbon paddle which left it with a tiny chip on one face. :frown: (But what the heck - It was just one of FOUR paddles and the rest were still perfect.:D)

Looking at my records, my blades/paddles were 13.7x35.3x7.3 compared to the minimum limits of 11.6x34.9x6.9mm. And my front bush was 0.632" compared to the max limit of 0.6354". (Sorry for mixing metric and Imperial - I often do that :D) Oh - And I see I actually replaced the input shaft oil seal too (30mm OD x 16mm shaft x 7mm thick) which cost me $6NZ. And the new O-rings - one for each side - cost me $1.50NZ each. ......That was in January 2007.

:cheers:

PS. After taking mine apart (and reassembling it), I read threads on MUD where people say their drive-splines have worn out. But I don't recall seeing any problems with mine.

So I would leave it alone personally. If mine is anything to go by, they're built to last forever with zero maintenance.
 
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Well I took mine apart after 238,857kms and 28 years service and found nothing really needed attention.

In fact, the pump was probably worse afterwards because I accidentally dropped one carbon paddle which left it with a tiny chip on one face. :frown: (But what the heck - It was just one of FOUR paddles and the rest were still perfect.:D)

Looking at my records, my blades/paddles were 13.7x35.3x7.3 compared to the minimum limits of 11.6x34.9x6.9mm. And my front bush was 0.632" compared to the max limit of 0.6354". (Sorry for mixing metric and Imperial - I often do that :D) Oh - And I see I actually replaced the input shaft oil seal too (30mm OD x 16mm shaft x 7mm thick) which cost me $6NZ. And the new O-rings - one for each side - cost me $1.50NZ each. ......That was in January 2007.

:cheers:

PS. After taking mine apart (and reassembling it), I read threads on MUD where people say their drive-splines have worn out. But I don't recall seeing any problems with mine.

So I would leave it alone personally. If mine is anything to go by, they're built to last forever with zero maintenance.
Interesting! Amazing how well these Toyotas were made to have that little wear after all that time.
 
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I've known diodes and transistor as well as many other electronic bits to do the weirdest stuff. I have been an electronics techie for over 30 years, it has shown me to look for the simple things first but to expect the bizarre.
(off topic)When I started components were the size of cockroaches, now they're the size of cockroach excreta.

The shorted/grounded winding theory may also be a cause, the diode pack will need to be disconnected to check it out. You will need to compare the resistance/impeadence of each of the windings (you'll need a good digital multimeter with a low ohms scale or preferably an LCR meter for it, a $10 ebay cheapy won't be good enough). As well as checking each winding against the body of the alternator, with a megger (a high voltage ohm meter) .
The theory is, each winding should have the same resistance/impeadence as the other two within say 5%. There should not be any reading between any of the windings, or from a winding to the body of the alternator.

You said that you ran the alternator without the regulator, and it didn't charge. That's because the "field"windings are fed power from the regulator. No regulator, no excitation of the field windings, no volt generation. There is residual magnetism which may induce some power generation but not a lot.

I bet your learning heaps about stuff you didn't care for..LOL.
 
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Well i got the alternator back from the shop and in typical Toyota fashion there's nothing wrong with it. I must of went wrong somewhere. So i will put it back in this weekend but where do I go from there?
 

Ron R

Drive a Landruiser, enjoy life
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Well i got the alternator back from the shop and in typical Toyota fashion there's nothing wrong with it. I must of went wrong somewhere. So i will put it back in this weekend but where do I go from there?
If the alternator is fine, only two options remain:
Regulator
and/or
Connections.

If you are sure the regulator is good, check thouroughly the connections between alternator and regulator and regulator and battery. Be sure to check the grounds! Check or the connections are clean and tight.
 
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STIFFLER, measure voltage across battery as you increase rpm on engine, at around 1000 rpm give or take it should be at around 28V and not increase much further than that with higher revving and should not drop by switching on beams or other high amp stuff.
If you get other than that then its most likely your regulator or like Ron R says, connections. If you have not done so check your battery cables, both ends on the negative and all the leads/connections from and to regulator/alternator.
 
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well I got it all back together again and it was 24.4v AGAIN.. So i let it idle for a few mins and then all of a sudden it went to 28.8 and stayed there at idle. Turned it off and it did all over again but this time it idled at 29.8 volts. In the process of doing things i noticed something broken it is up bu my voltage regulator and it is made out of ceramic (i think) here is a pic maybe the pro's can tell me what it is ? how to fix it? And it this my proplem?

Thank you guys for everything so far I feel we are getting close to a break through..
That is the voltage regulator to thr right against the firewall
DSC01917.JPG
 

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